Black Friday shopping has plenty of potential pitfalls. Your shoes might give you blisters. You could forget to bring a snack to eat while you wait in line. Or the item you are looking for could be sold out. These mistakes might be annoying, but there area some errors that can cost you money. We asked a roster of experts to tell us the biggest mistakes people make on Black Friday. You already have a to-do list. Here’s your don’t-do list.

1. Paying full price for add-ons. Don’t undermine your savings by buying accessories like cables and batteries at list price, says Dan de Grandpre, CEO of DealNews.com. Stores display these items prominently and conveniently for a reason. Especially with electronics, the accessories you need to get are strictly commodities; one store’s isn’t going to be measurably different from another’s in quality. Yes, it’s a little more effort, but these are the kinds of items online shopping was invented for.

2. Not bothering to comparison shop. “One mistake is assuming that something in a store, simply because it’s on sale on Black Friday, is a good deal,” says Jim Wang, founder of the blog Bargaineering.com. “It might be a decent deal, but you could do better going online.” In fact, it’s gotten easier to do the Black Friday sale experience without having to leave your house — or even wait until Friday. Many online retailers, along with some brick-and-mortar chains, are rolling out their holiday specials throughout this week. If you do hit the mall on Friday, though, most of our experts strongly suggest taking a tablet or smart phone with a price-comparison app or two so you can make sure you’re getting the real-deal best deal.

3. Buying toys too early — or too late. No matter what the ads say, you’re not going to get the best deals on toys on Black Friday, says de Grandpre. “Toys in general are almost always cheaper in the first two weeks of December,” he says. At mass-market stores that aren’t stocked with a huge supply of toys year round, “Those toys have an expiration date. Those toys are not going to move after Christmas,” he says. But on the other hand, waiting until the last possible second isn’t the best tactic, either. “If you wait too long, five to seven days before Christmas, prices climb again because they’re getting the procrastinators,” he says.

4. Getting the wrong features on a TV. TVs are a hugely popular Black Friday door-buster, and Gary Merson, editor of TV blog HDGuru.com, says a lot of people make the mistake of trying to score the cheapest set they can without considering whether it meets their needs. On LCD or LED TVs, one feature is the refresh rate. Your choices are generally 60 hz or 120 hz, which refers to the number of times per second the picture changes. “120 hz gives better motion resolution than 60 hz, so that’s something people who watch sports or action movies should consider,” he says. Also, while manufacturers have been talking up 3-D and smart TVs, the catch with 3-D is that there’s very limited content available, Merson says. “Unless you’re into movies and have a 3-D Blu-ray player, then it’s probably not that big of a deal.” Smart TVs let you stream content from the Internet, but you can get the same result with a “dumb” TV and an external streaming device like Roku or Apple TV that costs a hundred bucks or less.

5. Getting the timing wrong. Many of our experts pointed out that Black Friday actually starts at midnight or even earlier this year. Stores like Sears and Walmart are rolling out door-busters starting on Thanksgiving night, and many big chains are staggering the hours of their openings and their sales. If you’re bound and determined to get that dirt-cheap TV, make sure you’re not going to get there hours after they’ve sold out.

6. Settling for something more expensive. This brings up another point about door-busters. There are usually only a few of them, sometimes as few as two items per store. Walmart instituted a guaranteed availability of some sale items this year, but that’s the exception rather than the rule. In other words, if you’re not reading this on a mobile device while shivering in a sleeping bag on the sidewalk outside the store by now, you’ve probably missed your chance. Stores don’t mind practically giving away a few things because they know most of the other people in line will want to get something for their time and numb toes, so they’ll sell lots of other stuff that isn’t the deal those shoppers were coming for. Don’t be one of those people.

7. Opening a bunch of store credit cards. Yes, you’ll probably get 10% or 15% off. You may even get to cut a monstrous checkout line. But signing up for store cards left and right can leave you with a credit hangover that lasts well into the new year, says John Ulzheimer, president of consumer education at SmartCredit.com. The potential damage starts before you’ve even taken your bags out of the store. “Retail-store inquiries are among the most damaging type for your credit scores, and they can impact your scores for 12 months,” he says. The damage is cumulative and increases with each additional card you apply for. What’s more, store cards tend to have a combination of high APRs and low credit limits, which can catch you if you don’t pay off the whole balance by the due date or if you max it out. “Low limits are problematic for your scores because the cards can be heavily leveraged even with modest spending,” he says.

8. Not reading the fine print on price-matching offers. “A popular move for top retailers such as Best Buy and Target in 2012 is their claimed price-matching programs,” says Brad Wilson, founder of BlackFriday2012.com and BradsDeals.com. Even though some of these deals claim they’ll match prices of online retailers like Amazon, “the catch is that many of these items, electronics especially, now have a unique model number assigned to each retailer. For example, the exact same Toshiba 42-in. LCD TV would have a unique model number, hence excluding it from any price-match guarantee.”

The number one mistake is re-inforcing the awfulness that IS Black Friday. It starts earlier and earlier, and the sales don't actually get any better, they just tell you they are. People AREN'T spending more money, they're spending the same amount over a slightly longer period of time. I don't spend more simply because you have an earlier sale, that's simply flawed thinking.

And those who work in retail deserve the time at home with family on Thanksgiving. I refuse to do business with ANYONE of Friday. It's simply not necessary, and only undermines our American holiday of Thanksgiving.

That's why you start in January when the stores are marking down the stuff they couldn't sale and during the year, look for sales...like for weather clothes for next year or toys that are reduced. Always look at the fine print on ALL ads and coupons. Nothing like standing in line for 2 hours to check out and then find out the store doesn't accept the coupon b/c of the fine print. Thank goodness my Xmas shopping in done and I would say that 95% of the stuff I bought was on sale or marked down.

The point about toys is really, really true--there are better deals later, and equivalent deals any day from now until Christmas. Also, children's interests change so fast that buying a month before Christmas may mean you don't have money for what the kids are going to decide that they want two or three weeks from now.

Black Friday is increasingly becoming more popular, despite many people claiming they stay home. Check out this awesome infographic that outlines some of the history and the amazing numbers behind Black Friday: http://sortable.com/blog/black-friday-infographic/